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New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

smcleod.net

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Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#11
post #4

Wouldn't HiDPI be 1080p@2x? Is that still available?

Yeah I'm not sure what the point of this article is really or am I probably misunderstanding something? There's no such thing as 4K HiDPI on a 4K monitor. That would be 2160p @ 2x on an 8K monitor. 4K at 100% scaling looks terrible in general across every OS.

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#14
post #4

Wouldn't HiDPI be 1080p@2x? Is that still available?

Yeah. I don't get it. If you've got a 3840x2160 display, intended use on macOS as a 1920x1080@2x display, what is the advantage of using a 7680x4320 buffer? Everything is drawn at twice the width and height - and then gets scaled down to half the width and height. Is there actually a good reason to do this?

(I use my M4 Mac with 4K displays, and 5120x2880 (2560x1440@2x) buffers. That sort of thing does work, though if you sit closer than I do then you can see the non-integer scaling. Last time I tried a 3840x2160 buffer (1920x1080@2x), that worked. I am still on macOS Sequoia though.)

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#16
post #10

Well, it sounds like a real issue, but the diagnosis is AI slop. You can see, for example, how it takes the paragraph quoted from waydabber (attributing the issue to dynamic resource allocation) and expands it into a whole section without really understanding it. The section is in fact self-contradictory: it first claims that the DCP firmware implements framebuffer allocation, then almost immediately goes on to say i…

I think you are probably right--it's a real problem.

As an article, it is not 100% coherent, but there is a valid data and a real problem that is clear.

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#18
post #7

Send it to Tim Cook email. It worked for me fixing DisplayPort DSC bug. After Catalina, later MacOSes lost ability to drive monitors at higher than 60Hz refresh. Apple support tortured me with all kinds of diagnostics, with WontFix few weeks later. Wrote email and it got fixed in Sonoma :) https://egpu.io/forums/mac-setup/4k144hz-no-longer-available...

Thank you

Re: New Apple Silicon M4 and M5 HiDPI Limitation on 4K External Displays

#19
post #9
post #4

Wouldn't HiDPI be 1080p@2x? Is that still available?

Yeah if I understand it correctly, this is more like 2160p@2x which is... unusual?

Yes, I would actually be surprised to learn that mode is available on any system. I’ve never seen that anywhere, though I only have a M1 Pro and an M4 Pro (and various Intel Macs).

You’re rendering to a framebuffer exactly 2x the size of your display and then scaling it down by exactly half to the physical display? Why not just use a 1x mode then!? The 1.75x limit of framebuffer to physical screen size makes perfect sense. Any more than that and you should just use the 1x mode, it will look better and perform way better!

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